GNU adns 1.4 and earlier uses a fixed source port and sequential transaction IDs for DNS requests, which makes it easier for remote attackers to spoof DNS responses, a different vulnerability than CVE-2008-1447. NOTE: the vendor reports that this is intended behavior and is compatible with the product's intended role in a trusted environment.
https://www.exploit-db.com/exploits/6197
http://www.openwall.com/lists/oss-security/2008/09/16/4